1. Mendel, Pea Plants, and Inheritance Patterns AP Biology Fall 2010

2.  Late 19 th century, natural selection suggested that a population could evolve if members show variation in heritable  Variations that improved survival chances would be more common in each generation ◦ In time, population would change or evolve

3.  Theory of Natural Selection did not fit with prevailing view of inheritance ◦ Blending  Blending would produce uniform populations; such populations could not evolve

4.  Many observations did not fit blending ◦ White horse and black horse did not produce gray ones

5.  Gregor Mendel used experiments in plant breeding and knowledge of mathematics to form his hypotheses

6.  Mendel used the garden peas for his experiments  This plant can fertilize itself; true breeding varieties were available to Mendel  Peas can be cross fertilized by human manipulation of pollen  Self fertilizing: flowers produce both male and female gametes  True breeding: successive generations will be like parents in one or more traits ◦ White flowered parent plants give rise to white flowered offspring

7.  Mendel hypothesized that clearly observable differences might help him track the trait and identify inheritance patterns and heredity

8.  Genes: units of information about specific traits, each located at a particular locus on a chromosome  Homologous Chromosome: diploid cells have 2 genes (a gene pair) for each trait- each on a homologous chromosome  Mutation: alters a gene’s molecular structure  Alleles: are various molecular forms of a gene for the same trait ◦ Page 171, figure 11.4

9.  True Breeding Lineage: occurs when offspring inherit identical alleles, generation after generation  Hybrid Offspring: what non-identical alleles produce  Homozygous: when both alleles are the same  Heterozygous: when the alleles differ  When heterozygous one allele is dominant (A) and the other allele is recessive (a)

11.  Homozygous dominant: AA  Homozygous recessive: aa  Heterozygous: Aa  Genotype: is the particular alleles an individual carries  Phenotype: is how the genes are expressed physically (what you observe)  P: true breeding parental generation  F1: first generation offspring  F2: second generation offspring of self fertilized or intercrossed F1 individuals

12.  Jeopardy